Internal combustion engines may be cooled by circulating a suitable coolant through various passages or cavities in the engine.
In direct injection engines, approaches are known which route coolant over the fuel injectors where it is simple to package. However, many direct injection engines have been developed without cooling under the fuel injectors near the combustion chambers. Heat from the combustion chamber will make these regions hot. Packaging coolant in the form of a traditional water jacket core may not be possible.
In some approaches, sand core may be packaged beneath the injector to create coolant cavities. However, due to wall and sand thickness requirements, the resulting water flow may be far from the combustion chamber reducing the effectiveness of the cooling. Further, such sand cores may be large and difficult to produce. In such approaches, additional metal and sand cores employed to route coolant near hot regions of a fuel injector (e.g. adjacent to the combustion chamber) may result in an increase in material and construction costs and may require modification to existing components in the engine block. Such approaches may lead to higher costs, less effective cooling, and additional weight, for example.
In order to at least partially address these issues, in one example approach a direct injection engine is provided. The direct injection engine, comprises: a first and a second coolant passage each traversing from a cylinder block to a cylinder head; an angled fuel injector bore in the head; a recess positioned between the first and second coolant passages, the recess being depressed in the head toward the injector bore; and a head gasket having a slot fluidically coupling the first and second passages with the recess.
In this way, coolant may be routed beneath a direct injector near a combustion chamber resulting in an increase in cooling of the injector. Further, in such an approach, the injector may be cooled with a minimal amount of additional features, e.g., without additional metal parts or sand cores in the engine block, thus reducing costs associated with manufacturing and installation of new components, if desired.
Further, by routing coolant beneath an injector bore in this way, a relatively smaller amount of coolant (e.g., as compared with an amount of coolant flowing in the first and second coolant passages) may be utilized to cool a fuel injector. A pressure differential between the first and second coolant passages may cause a relatively small amount of coolant to “leak” into the recess beneath the injector bore. The relatively small amount of coolant delivered beneath the injector bore may be sufficient to reduce temperatures of a fuel injector installed therein.
Additionally, an amount of injector cooling may be adjusted, e.g., by adjusting a size and/or shape of the slots in the gasket. Further, casting weight may be reduced, e.g., via the recesses formed in the cylinder head. Further still, increasing injector cooling may contribute to a more durable system and may lower fuel temperatures which may result in engine performance benefits.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.